Add a close event to MessagePort #914
Description
Request for Mozilla Position on an Emerging Web Specification
- Specification title: Add a close event to MessagePort
- Specification or proposal URL (if available):
- Explainer URL (if available):https://github.com/fergald/explainer-messageport-close
- Proposal author(s) (
@-mention GitHub accounts): @fergald @nononokam - Caniuse.com URL (optional):
- Bugzilla URL (optional):
- Mozillians who can provide input (optional): @asutherland
Other information
Currently, there is no timely and reliable way to detect when a MessagePort becomes disentangled, which makes it difficult to release resources associated with ports. This issue has a long discussion of the problem and potential solutions. Some users have used the unload event to detect disconnect, but it is deprecated. Therefore, The approach available now is to hold a MessagePort in WeakRef and periodically check if this port has been garbage collected by using deref() or to make use of a page-hide event, which is quite inefficient.
So, I propose adding a close event. For example, if there are two entangled ports, portA and portB, and portA is closed, the close event is fired on portB.